Not the whole biomass. Just the mass of CO2 that falls into the category of "collects in your house when the windows are all closed". I'm not going to argue that it's a small number nor that it's easy to take care of a large array of plants. It's just that everything else short of using plants seems like a simple offloading of CO2 elsewhere (e.g. opening windows). I'm not satisfied with such selfish solutions.

You're right that the practical consideration is important. It needs to be addressed and engineered to be made practical.

On top of that maybe we eat too much, but that's a off topic.